The ConnectionString property has not been initialized. Error? - vb.net

Question

Imports System.Data.OleDb
Public Class Money_Donated
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
All_Donations.Show()
Me.Close()
provider = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source ="
dataFile = "C:\Users\Derick\Desktop\ICE 9\Donors.accdb"
End Sub
Dim provider As String
Dim dataFile As String
Dim connString As String
Public dr As OleDbDataReader
Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
Dim myConnection As OleDbConnection = New OleDbConnection()
myConnection.ConnectionString = connString
connString = provider & dataFile
TextBox1.Clear()
myConnection.Open()
Dim str As String
str = "SELECT * FROM Donors WHERE (Code = '" & Donators121.Amount_of_money_donatedTextBox.Text & "')"
Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
dr = cmd.ExecuteReader
myConnection.Close()
While dr.Read()
TextBox1.Text = dr("Description").ToString
End While
End Sub
End Class

Answer 1

It looks like you are setting the connection string with an empty string. You need to swap the line connString = provider & dataFile with the line myConnection.ConnectionString = connString. Otherwise, you are setting the connection string of the connection object to an empty string.
Dim myConnection As OleDbConnection = New OleDbConnection()
connString = provider & dataFile
myConnection.ConnectionString = connString
TextBox1.Clear()
Also, as OneFineDay suggests you should use parameters rather than creating SQL strings as your code is currently vulnerable to SQL injection attacks.